Some computer systems include arrangements in which certain terminals are public and may operated by many different users. For example, a computing system may include a terminal that is available for anyone in the public to use. In order to customize a public terminal for an individual's use and/or to block unwanted users from accessing the system through the public terminal, a system may require a user to present a credential, such as a personal identifier and/or passcode. The credentials may allow the user to access user-specific applications, databases, and information.
In the example context of a financial computer network, automatic teller machines (ATMs) and point-of-sale (POS) systems may act as public terminals. For example, ATMs may be located on city streets, accessible to anyone in the area. And, a user of that public terminal may present a payment card, sometimes in conjunction with entry of a personal identification number (PIN), to access the public terminal, for example, to complete a purchase or withdraw currency. However, proper authorization depends on the user being authenticated so that the system can trust that the user is who he or she purports to be. Otherwise, the system has no way to determine that a user only view and manages funds of his or her own accounts.